/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/MeshNormals.h
Initialize the given Mesh with per-face normals, ie separate overlay element for each vertex of each triangle.
static void InitializeMeshToPerTriangleNormals ( [FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) * Mesh )